>So far I have only located 3 Kits to retrofit S4's. >1. Audi-Hoppen Kit, a huge 2 Pot 4pc. pad as used on the S6+. >2. AP 6 Pot Kit. >3. KVR 4 Pot AP kit. >Anybody know of any others? Chck this site http://www.ultimategarage.com/ Mark Pollan, '86 5KCTQ